Need a bit more info mate, what material, what process, can you get to both sides? Off the top of my head I'm thinking MIG, chamfered with a root gap, double 'v' preped, if you can get to both sides to back grind it, or single 'V' with a ceramic backing tile. Obviously there are other options (track mounted mig. sub arc etc..), but again, more info needed.
Edit, just saw that you posted this in the ARC section, Depends on the material, but I'd probably use the same/similar set up, root it with 7016/18 then fill it with a 7024 or a big 7018 depending on the position/aplication/access to both sides etc..
Common or garden mild steel, seam welded along the longer sides.
Personally, I'm thinking also of a double vee, arc welded with 1/4" or 5/16" 7018 rods, though possibly others for subsequent passes. Preheating the metal to perhaps 150C using heat pads.
I'm thinking also of using some kind of intermittent weld (before seaming) to avoid possible distortion/cracking.
Delgado, it seems like we are on the same page, but I am interested to know what others think.
if you cant get to both sides i would consider welding a bit of 40x5 to the u/side of the laps first then leaving a 20mm gap between the plates and filling the gap with fillets of 7024 or what ever you would use (dont use a 2.5 7016 for this bit) this would save on lots of grinding prep especially if a single v is needed.
possibly tack some 40x5 to middle of sheets if these are laying flat against a concrete slab so they are supported better? dont know application though.
distortion could be a bit of a problem i would imagime if they need to be nice and flat after installation, 20mm plate to back of lap and countersunk M20 bolts an option?
let us know what these are for and what you decide
cheers
If its common or garden mild steel you dont need pre heat, I wouldnt do it cold, just hand warm will do.. You could put a 60o included angle on it and a 2mm root face. Push a 3.2mm 6013 into the root, then fill it with 7024s maybe a couple of 4mm and then 5mm (I doubt you will get 6mm). When full turn it over grind the back into a U shape and put a sealing run in.
If you want to keep it flat weld some strongbacks across it. Pieces of plate stitch welded at 90 degrees to the plate being welded.
Alternatively you can MIG it from root to cap with 1.0mm or 1.2mm
The idea is to manufacture a flat plate that is 3 metres wide, 6 metres long, and 20mm thick. To do this will involve butt welding 4 each, 3m x 1.5m plates together. Each of these plates weighs in at 720kg's. The total weight will therefore be roughly 2880kg. We can get at the welds from above, and below. Once the plate is welded, we dont want to turn it over, or move it. In other words, it will be welded in situ. The one thing that we will have to do thoughh is grind back the welds until they are flush. Some kind of strengtheners can be used during manufacture, but they will have to be removed upon completion. If possible though, we would like to avoid this.
Use a 60 vee, prep a 2mm face and leave a 2mm gap (stick a 2mm rod inthe gap). Use either MIG or a 7016 for the root and then fill it with whatever you want. You will need to weld strongbacks on it or it will distort. You can remove these when complete.
Might also be an idea to tack some 'v'/'x' shaped run off tabs onto the ends of the prep aswell, whatever youve got laying around, 3/4mm sheet should do it. Peronally, For the root I'd use a single 'V' prep with about a 2/3mm root face and a 3.5mm gap, a copper backing plate or tile and have at it with a 3.25mm 7016/18, you should only have to get underneath it to tidy it up a bit with the grinder/repair and bits you're not happy with. Any of the other ways you've been told should be fine too, whatever you find easiest.
Thinking outside the box here, have you enquired about a 6x3 sheet...?
6m length should be readily available, id expect 2.5m wide to be easier to get than 3m.
Save yourself a lot of effort.
Thinking outside the box here, have you enquired about a 6x3 sheet...?
6m length should be readily available, id expect 2.5m wide to be easier to get than 3m.
Save yourself a lot of effort.